You take ONE roll of a 20-sided number cube to determine your fate. If you roll a number greater than or equal to 8 , you are able to defeat the troll. But if you roll a prime number, the bridge will give out with you still on it. What are Orgoth's chances of safely reaching the other side of the canyon?

Answer 1

There are 20 possible outcomes when rolling a 20-sided number cube.

Of those 20 outcomes, there are 12 that are greater than or equal to 8.

There are 8 prime numbers on a 20-sided number cube: 2, 3, 5, 7, 11, 13, 17, and 19.

Therefore, there are 8 outcomes that would cause the bridge to give out.

To find Orgoth's chances of safely reaching the other side of the canyon, we need to find the probability of rolling a number greater than or equal to 8 and subtract the probability of rolling a prime number.

Probability of rolling a number greater than or equal to 8: 12/20 = 0.6

Probability of rolling a prime number: 8/20 = 0.4

Therefore, Orgoth's chances of safely reaching the other side of the canyon are:

0.6 - 0.4 = 0.2 or 20% chance of success.